There is known a brake system, as a vehicle brake system, in which a pump is provided on piping through which a brake fluid flows, and the pump is driven by supplying electric power to an electric motor of the pump so as to cause the brake fluid to flow in a predetermined direction in the piping. The viscosity of the brake fluid increases as the temperature of the brake fluid decreases, and this makes it difficult for the brake fluid to flow smoothly in the piping. To deal with this drawback, for example, JP-H04-303041-A discloses a vehicle braking control unit in which in the event that a temperature of a brake fluid detected by a temperature sensor is equal to or lower than a preset temperature, electric power that is supplied to a driving motor of a pump is increased so as to increase the driving torque of the pump.
Incidentally, in the prior art technique, the electric power that is supplied to the driving motor is increased in the event that the temperature of the brake fluid is equal to or lower than the preset temperature. However, there is described nothing concerning the extent to which the electric power to be supplied is increased. Due to this, in the prior art technique, there are fears that electric power is consumed more than required in the event that the temperature of the brake fluid is slightly lower than the preset temperature. In addition, in the event that the temperature of the brake fluid is much lower than the preset temperature, the delivery pressure of the pump becomes insufficient, leading to fears that the brake fluid does not flow smoothly.